The present invention is directed to bicycle brake devices and, more particularly, to a bicycle brake cable retainer, a bicycle brake lever assembly, a bicycle brake cable connector, and a bicycle brake system.
A bicycle brake system commonly comprises front and rear braking devices for applying braking forces to the front and rear wheels, front and rear brake levers mounted on the handlebar and designed to operate the front and rear braking devices, and brake cables secured to the front and rear braking devices and to the front and rear brake levers. Each brake cable comprises an inner wire that slides within an outer casing, wherein the inner wire is connected at one end to the brake lever and at the other end to the braking device. The outer casing ordinarily has one end mounted to a bracket for the brake lever and another end mounted to a bracket for the braking device.
The braking device comprises a braked member that rotates with the wheel and a braking member capable of coming into contact with the braked member. The braked member usually is the rim or hub of the wheel. The braking device for applying the braking force to a wheel rim may be a caliper brake or a cantilever brake, whereas the braking device for applying the braking force to a wheel hub may be an internal expanding brake in the form of a band brake, disk brake, roller brake, or the like. The braking device usually includes a play adjusting mechanism for adjusting the gap between the braked member and the braking member (that is, the play of the braking device) when the brake lever is not being operated. In a typical mechanism, an outer retainer for securing the outer casing is screwed into the braking device, the retention position of the outer casing is shifted in the axial direction of the cable by the rotation of the outer retainer, and the play is thus adjusted. This operation also sets the brake timing of the braking device.
A cable connector that allows the front and rear braking devices to be operated simultaneously with a single brake lever is disclosed in JP (Kokai) 4-2588, for example. In that device, the cable connector is disposed in the middle of the front and rear brake cables. The cable connector has a connection member for connecting exposed portions of the inner wires of the front and rear brake cables together and a bracket that allows the connection member to move. Outer retainers for securing the portions of the outer casings extending toward the braking devices and the portions of the outer casings extending toward the brake levers are disposed at opposite ends of the bracket. In a brake system having such a cable connector, both inner cables are pulled when a single brake lever is actuated, thus making it possible to obtain enhanced frame stability and stabilized braking characteristics. In addition, braking can be accomplished by operating either the left or right brake lever, thus making it possible to operate the brake levers with ease and to increase the service life of the braking devices by dispersing the braking force.
Since both inner cables are pulled when a single brake lever is actuated in such a system, the inner cable secured to the unactuated brake lever extends further from the outer casing, sags, and causes the brake lever to become loose. Furthermore, since the front and rear inner cables move simultaneously, the front and rear brake timing may vary considerably if the play is markedly different for each braking device. Since the inner cable connected to the rear braking device is longer than the one connected to the front braking device, it tends to stretch more during use. As a result, the rear brake timing gradually shifts away from the initial timing during use, thus making it necessary to readjust the amounts of play for the front and rear braking devices.
Optimally, the play of the front and rear braking devices should be kept the same or be limited to a specific difference. In a conventional braking device in which braking force is applied to the rim, the play can be kept constant by equalizing the gap between the brake shoe and the rim for the front and back wheels. In practice, however, this is difficult to do. In systems in which braking force is applied to the wheel hub, the braking member brought into contact with the drum is disposed inside the braking device, thus making it impossible to see the gap formed between the braking member and the hub. This makes it even more difficult to provide the front and back braking devices with the desired amounts of play.